The invention relates to a method and a device for cutting underwater structures and particularly for cutting underwater structures such as, for example, ducts, pillars supporting offshore platforms, or the like and which are made mostly of steel or other metals or of mixed materials, such as steel or other metals and cement, or the like.
At present, said structures are cut manually by teams of underwater workmen who operate directly on the spot with suitable tools such as, for example, thermal lances, electrodes for underwater cutting, grinders, pipe-cutters, etc. However, these operations are tiresome, expensive and involve considerable fatigue and risks for the operating personnel. The high costs of these operations are determined by the considerable duration of the cutting operations, by the necessity to engage highly-specialized operating personnel in very dangerous conditions, and by the resulting necessity to provide adequate assistance means with a corresponding number of auxiliary operators. The operating conditions become even more difficult when the structures to be cut are of the composite type such as, for example, in case of elements constituted by concentric steel pipes whose interspaces are filled with concrete or cement. In effect, in these instances, the cutting through the interspace cannot be ensured even by the most sophisticated tools, so that the intermediate layer of cement must be broken down before acting on the inner pipes. The duration of these operations may last even several days.
Therefore, the invention is based on the problem of providing a method and a device for cutting underwater structures, which, thanks to a construction as simple and economical as possible, permit to carry out the cutting operations with extreme ease and rapidity, minimizing the risks and costs.